Telephone apparatus



J. S. TIMMONS.

TELEPHONE APPARATUS. APPLICATION FILED APR. I3. 1918.

Patented J an. 27, 1920.

2 SHEETS-SHEET I J. S. TIMMONS. TELEPHONE APPARATUS. APPLICATION FILED APR. 13. 1918.

Patented Jan. 27,1920.

2 SHEET$SHEET 2.

UNITED STATES PATENT OFFICE.

JOHN S. TIMMONS, OF NEW YORK, N. Y.

TELEPHONE APPARATUS.

Specification of Letters Patent.

Patented Jan. 27, 1920.

Application filed April 13, 1918. Serial No. 228,311.

other in. a satisfactory and intelligent manner, and especially is this so when the operator and attendants are necessarily more or less widely separated. This difliculty of communication is especially objectionable in the matter of aeroplanes, when the noise of the engines and propellers. completely drown out the voice of the operators to such an extent that not only is it impossible to communicate but makes it also impossible to. hear other aeroplanes which may be approaching from 'rearwardly or side directions until they are dangerously close. The same general difliculties arise in proximity to large guns in warfare and in fact, under numerous conditions where a number of persons are necessarily cooperating in conjunction with the operation of noisy machinery or apparatus.

My invention has for its object, the provision in a telephonic system of communication between the operators and attendants, of certain features of construction in the head sets comprising the transmitters and receivers, which will enable the said op erators and attendantsto freely inter-communicate by conversation, notwithstanding the objectionable noises aforesaid; and my invention, furthermore, particularly 'embodies special features of construction in respect to the transmitter, whereby the same may be operated directly by muscular action of the operator and without being affected directly by air vibrations adjacent to the said operator or produced by articulate speech. H

Ordinary telephonic communication is not feasible under the noisy conditions above enumerated, because the vibrations of the air caused by articulate speech and intended to be the means to vibrate the diaphragm of the transmitter are, themselves, interfered with and their distinctiveness obliterated by the particular vibrations due to the causes enumerated, and more particularly such as the operation of the motors, firing of the guns or noises from operating machinery generally. My invention, therefore, comprehends a transmitter having a construction of such form as will be accurately operated by the facial vibrations produced by the operator in the act of talking, but which will not be affected materially .by the air vibrations in the vicinity of the operator.

In the special application ofmy invention to various uses, there would be more or less variation in the circuit connection, switches, etc., according to the number of receiversto beput into communication with the transmitter, but such variation in the circuits, etc., are not of importance in con- -s1der1ng the articular invention herein claimed, and I do not restrict 'myself in such respects; but in all cases, the special construction of the transmitting instrument and its adaptability in use, is substantially the same and embodies a construction in which the transmitter is bodily put into vibration by direct application to the throat or check or other vibrating part of the body of the operator, and whereby the microphone of the transmitter is affected wholly by the muscular vibrations of the operator while being unaffected by the air vibrations produced in the vicinity of the operator. In an apparatusof this character, the operator may talk in an ordinary tone, or even under conditions in which he cannot hear his own voice, and yet the transmission by use of my improved transmitter will be distinctly and clearly heard by the person to whom the receivers are attached. In general, the construction of the=transmitter involves the complete exclusion of the air vibrations from the diaphragm and microphone, while at the same time permitting the operator to talk in a natural manner and with unconfined lips, the operation of the microphone of the transmitter being effected solely under the muscular action and preferably of the throat or cheek of the operator, as is more fully described hereinafter. 7

In the preferred form of my improved transmitter I provide an air tight case having means for adapting it to rest snugly against the throat or other part of the head or body of the operator, andcombine with the said-case,- a microphone device arranged,

-electrodes of the microphone may be put into vibration by a. bodily vibration of the inclosing case, and the last mentioned electrode being provided with sufficient weight, will through the action of inertia, tend to resist vibration and consequently enable a relative vibration between the two electrodes to take place, affecting the resistance of the microphone and in that manner controlling the undulatory current required for articulate speech. The above stated actions are the result of the bodily vibration of the solid outer casing by muscular action of the operator and without having its contained diaphragm affected bythe surrounding air vibrations.

' My invention also consists of improvements hereinafter described whereby the above objects and results are attained, said improvements comprising certain organization and combination of parts which are fully described hereinafter and more particularly defined in the claims.

Figure 1 is a perspective view illustrating a head set used by .an operator and having my improved transmitter applied thereto; Fig. 2 is a perspective view illustrating the adaptation of the head set to a helmet; Fig.

8 1s a sectional view through my improved transmitter; and Fig. 4 is a rear View of my improved transmitter, with the rear cover plate removed to show the interior construction.

The transmitter shown in Figs. 3 and 4 is constructed as follows: 2 is a case which may be made of aluminumor other suitable material and is of a rigid construction.

.This case is provided with ahollow chamber 6, has its front portion 3 arranged on an f incline to the axial length of the case, and

its rear open end provided: with a screw threaded cap or cover plate 7 which is screwed down tightly to close the chamber when the transmitter is fully assembled.

The front portion of the case 2 is provided at top. and bottom respectively with strap or web loops 4 and 5-, through which the strap or web 27 of the head harness extends for holding the transmitter tightly against the throat of the operator. As shown, these strap or web loops 4 and 5 are arranged slightly back of the front face 3 of the casing 2, so that they will not interfere with the positive contact of said face with the throat or vibrating portion of the body of the operator.

' Within the hollow interior of the case 2 is arranged the microphone,'which in some respects may embody features of common construction, but the arrangement of the microphone itself and the manner of insuring vibration of the diaphragm is materially. different from transmitters heretofore in use, andl will now describe-the details of my improved construction.

Within the bottom 8 of the chamber 6, I arrange metal disk 9, to which is attached the carbon disk 11 constituting one of the electrodes. The diameter of the carbon disk is somewhat smaller than the diameter of the metal disk 9, and this latter is held tightly in place by the annular bushing 10. Resting upon the bushing 10 is the diaphragm 13 and this is clamped in position by the screw bushing or clamping ring 14 which is screwed into the case 2. 15 is a metal disk of smaller diameter than the interior of the bushing or ring 10 and rests against the inner face of the diaphragm 13, being held thereon by'a screw shank 16 and nut 17. To the inner face of the disk 15 is secured the carbon disk 19, (it being substantially parallel to carbon disk 11) and constitutes, with the disk 15, the other or movable electrode of the microphone. Between the carbon electrodes are placed the granular carbon particles, such as generally used in microphones. The diaphragm is preferably of mica and hence is nonconducting to the current; and to prevent short circuiting, the inner surface of the bushing or ring 10 is lined with paper 12 to keep the carbon granules out of contact with the said metal bushing 10. At the outer side of the threaded shank 16 and the nut 17 as will be clearly understood by reference to Figs. 3

and 4; I

To supply current to the microphone, I prefer to employ the following features of construction: The casing 2 is provided with a hub 22 having an aperture through it opening into the chamber 6; and the hub is further screw threaded'and fitted with a tubular clamping screw-bushing 23 whose threaded shank is tapered. Extending through the clamping bushing 23 and into the chamber 6 is a two wire cable 21,the wires at the inner end being separated as at 24 and 25, the former clamped under the nut 17 and hence connecting electrically with one electrode, and the latter soldered to the casing 2 and hence connecting electrically with the other electrode. By screwing in the bushing 23, it grips the cable and prevents any strain coming upon the microphone elements and also makes an air and water proof joint.

A very important feature in the construc tionof my transmitter, resides in the presence of the weight 18 upon the disphragm a 13, because this weight provides a mass in association with the diaphragm and movable electrode which, by its inertia, ofl'ers resistance against movement and consequently, when the casing 2 is bodily vibrated by the muscular effort of the operator in talking,

the movement of the electrode 19 of the diahragm is caused to lag in overcoming the inertia of the weight 18 and its connected parts. and in this manner vibrate in an effort to follow the vibrations of the case, the lag or phase difference causing the microphone to. become responsive. It is quite important that the weight shall be proportioned properly, because if it were too heavy it would make the instrument less responsive locate a part of the weight upon each side of the diaphragm, as shown. By properly adjusting the weight upon the diaphragm 13 to accord with its flexibility and otherwise providing sufficient carbon granules to suit the current to be employed, exceedingly clear articulation may be transmitted under the most adverse conditions of extraneous sounds in the air in the immediate vijcinity. Experience has shown that with this transmitter there are no noisy air vibrations possible which can materially interfere with clear sound transmission, and consequently the transmitter is excellently adapted for use in aeroplones and ordnance operations.

The diaphragm 13 may be of any suitable material other than mica and hence I do not restrict myself in this respect. This transmitter is quite small as compared with ordinary instruments, the actual size in practice being'only about one-third the size shown in the drawing,- the scale of the drawing being large for purposes of better illustration. The device is so small that it may be held under the chin without the least inconvenicnce..

The obliquity of the contact surface 3 to the parallel planes of the electrodes and diaphragm enables the transmitter to be held to the side of the throat as shown in Fig. 1, and at the same time cause the planes of the electrodes 11 and 19 and diaphragm 13 to be substantially vertical or upright to insure the granular carbon 20 of the microphone being maintained in electrical contact with both eelct'rodes.

'--While I have found that the best results are obtained when the transmitter is placed tightly against the neck near the larynx, nevertheless the transmitter may be otherwise positioned, as for example, higher up against the cheek, if so desired. In all cases, however, the free air vibrations are shut off from the diaphragm of the transmitter as well as in the case of the receivers. It is to be understood thatv'arious manners of holding the transmitter closely against the head or neck of: the operator may be employed and hence I do not restrict myself to any particular means for accomplishing this purpose, I have, however, shown in Figs. 1 and 2, by way of example, suitable means for applying my improved transmitter and receivers to the throat and ears, respectively, of the operator and I will now describe them in detail.

Considering now, the nature of the trans mitters and receivers in association, it is to be understood that so far as the internal construction of the receivers is concerned, I, in no wise, limit myself; but in outward construction, the receivers R areprovided with rubber covers or caps 7* which fit snugly about the ears of the operators either directly, as with the harness of Fig. 1, or indirectly, as when arranged in the hood or helmet as in Fig. 2. In Fig. 1, the two receivers R, R, are held in position to the ears by a strap or band 26 extending over the head, achin strap or web 27 extending under the chin and a back web or strap- 22 extending about the back of the head. These straps, webs or bands may be adjustable as x by suitable buckle devices S and if desired,

may be elastic. The transmitter T is held,

pilot or operator and so that the throat vibrations during speech will be transferred to the transmitter case 2. In securing the transmitter to the chin strap or web 27, the latter is threaded through the strap loop 4 and 5 and over the face 3 of the case 2, as shown in Fig. 3. The body is preferably of metal and quite small and vas the diaphragm operating portion, is intended to lie close upon the throat of the pilot and away from the region of his mouth, and so formed that no atmospheric sound waves are permitted to have access to the diaphragm. The transmitter is operated by the vibrations of the outer surface of the throat against which the transmitter rests; and in practice it has been demonstrated that in this manner,.speech in a low tone of voice may be transmitted with perfect clearness to the person usingthe receivers at the other station and be clearly understood, no matter how great the noise from the machinery and rushing of the air. Therecei'vers and transmitter are coupled with the outside circuits by a coupling plug switch 30 attached by cable 29 to the harness straps or' webs 27 and 22?, so that the operatormay readily connect his instruments with the outside circuits which may be attached to the aeroplane itself or which may lead to any distance if the apparatus .is used in connection with ordnance or other purposes on the ground. This coupling switch may be of any suitable construction and I do not limit myself in this respect. In Fig. 2 the receivers R, R, and transmitter T are inclosed in or associated with the hood or helmet 26 viding such contact, whether with the metal next to the skin or covered with a cloth for comfort, as will insure the mechanical vibrations of the skin surface acting as amotive force to vibrate the diaphragm as distinguished from operating it by vibrations propagated through the air.

e instruments give very loud transmission and do away with the disagreeable tones due to extraneous airv vibrations, which have the objectionable tendency of making the speaker believe that he is speaking louder than he really is and hence, therefore,

unconsciously talk too low to properly trans mit speech. By this improvement, he talks naturally and insures clear enunciatiom It will now be apparent that I have devised a novel and useful construction which embodies the features of advantage enumerated as desirable, and while I have in the present instance shown and described the preferred embodiment thereof which has been found in practice to give satisfactory and reliable results, it is to be understood that I do not restrict myself to the details, as the same are susceptible of modification in various particulars without departing from the spirit or scope of the invention.

Having now described my. invention what I claim as new and desire to secure by Letters Patent, is:

1. In a telephone transmitter, a closed case sufliciently rigid not to be affected by air vibrations, combined with a microphone entirely inclosed within the case and having one electrode directly connected to the case, a diaphragm secured to the case and provided with the other electrode, said diaphragm free to vibrate independently of neaaoae the case and having secured to it a part formed of suificient weight to provide an effective inertia to produce a difierence in phase vibrations of the two electrodes, and

means for holding the-case tightly to an operator so as to be vibrated bodily by,

bodily by muscular action caused by utter-- ing articulate sounds.

3. A. telephone transmitter having a microphone entirely shielded against air vibrations by an outer case, one electrode of the microphone rigidly secured to the case and bodily movable with it, and the other electrode of the microphone weighted and secured to the case through a flexible diaphragm, the'weighted electrode having part of its weight upon opposite sides of the diaphragm.

4:. A telephone transmitter having a hollow case substantially non-sensitive to sound vibrations of the air, combined with a microphone within and shielded by said case, one of the electrodes of the microphone wholly movable with the case and the other electrode of the microphone 'movably suspended within the case, and a flexible diaphragm having its perimeter secured to the case and its center secured to the movable electrode,

said movable electrode sufficiently weighted to cause the electrodes to vibrate out ofphase when the case is vibrated.

5. In a telephone headset for aeroplane pilots, etc., means arranged for fitting over the'hcad and having a strap under the chin, receivers positioned on said means adapted to extend over the ears, and a transmitter secured to the chin strap and arranged to be held tightly against the throat portion of the head, said telephone transmitter having a 'hollow case substantially non-sensitive to sound vibrations of the'air, combined with a microphone within and shielded by said case, one of the electrodes of the microphone wholly movable with the case and the other electrode of the microphone movably suspended within the case, and a flexible diaphragm having its perimeter secured to the case-and its center secured to the movable electrode, said movable electrode sutficiently Weighted to cause the electrodes to vibrate out of phase when the case is vibrated.

6. In a telephone headset for aeroplane pilots, a harness formed of webs arranged for fitting over the head and under the chin, receivers for the webs positioned mitter' arranged nearer one receiver than the other so as to: come over the throat of the operator to one side of the larynx.

8. A telephone transmitter comprising the following parts in combination, a case having a hollow chamber, an electrode fitted tightly in the inner end of the chamber, a diaphragm clamped to the case and fitting across the chamber parallel to the electrode, a clamping ring secured to the case for clamping the perimeter of the diaphragm in place, an electrode secured to the side of the diaphragm next to the first mentioned electrode, a weight secured to. the opposite side of the diaphragm and arranged to vibrate independently of the case,"

andv conductors electrically connecting respectively with the case and the vibrating electrode.

9. A telephone transmitter having an outer case formed with a rigid'surface for contact with the skin of the operator, said case having web loops at sides diametrically opposite and each arranged slightly to one side of the rigid contact surface soace to be unobstructed,

as to allow said sur combined with a head harness havin a web extending about the loops for holding the.

transmitter tightly to the skin of the operator.

10. A telephone transmitter having an outer case formed with a rigid surface for contact with the skin of the operator, said case having Web loops at its sides diametrically opposite and'arranged slightly to the rear of the rigid contact surface, combined with a chin strap extending over the rigid contact surface and backward about the loops for holding the transmitter contact surface tightly to the skin of the operator. I

'11. A telephone transmitter comprising an inclosing case having an inner chamber and an outer oblique non-vibratable contact surface adapted to be pressed against the 'neck of the operator,a microphone arranged planes of the electrodes and diaphragm in a substantiall vertical direction.

12. A telep one transmitter comprising a rigid case having an oblique contact surface and chamber open at the back, a microphone within the chamber and having its diaphragm and movable electrode near the 0 en end of the chamber, a cable extendin'g t rough the case to the outer side of the diaphragm and having a terminal connected with the diaphragm and its electrode, a removable cover cap detachably secured to the case'to tightly close the open end of the chamber, and means for holding the case ti htly to the head of the operator.

n testimony of which invention I hereunto set my hand.

JOHN S. TIMMONS. 

